The present invention relates to apparatus and methods for providing arc fault protection in a circuit and, more particularly, apparatus and methods for ensuring coordinated arc fault protection in hierarchical power distribution systems, such as those used in aircraft.
In a typical hierarchical power distribution system, power controllers with built-in arc fault protection function provide protection against arcing faults, overload protections and differential protections in the main feeder line as well as in the individual branched feeders.
The coordination of overload protections and differential protections between the main feeder lines and the branch lines are inherently guaranteed by the current ratings of power controllers themselves. However, if a particular arcing is present in the branched feeder, a typical power controller with built-in arc fault protection may trip the main feeder line in addition to the intended branched feeder line having the arc fault, such that the power supply is disconnected from the particular load having the arc fault, as well as from other loads powered by the same main feeder line. causing undesirable power interruptions to those loads.
Conventional arc fault protection schemes may include a physical communication between the main feeder line and the branch feeder line, as well as between separate branch feeder lines. Such a physical connection may be used, in conventional arc fault protection schemes, to permit coordination such that, when an arc fault is present in a branch feeder, only that branch feeder load control unit may trip. However, this physical communication link may result in additional issues in terms of cost, weight, timing, and data throughput, etc.
As can be seen, there is a need for an arc fault protection scheme that may provide coordination between the power controllers with built-in arc fault protection of the various branch circuits as well as of the main circuit. Moreover, there is a need to provide such coordination reliably without the need for a physical communication link between various circuits.